"New York City's competitive street food culture has created a thriving black market for mobile food vending permits issued by the Department of Health and Mental Hygiene. The city charges a mere $200 for most food-cart permits, which must be paid every two years when they are renewed. But it only issues 3,100 year-round permits plus an additional 1,000 seasonal permits—not enough to satisfy demand. Transferring or renting these permits to another vendor is illegal but everyone, including the city's Health Department, acknowledges, that it happens.
Demand for permits and their black-market prices continue to climb as street food's popularity soars. Some permits fetch as much as $20,000 for two years."
~Today's Wall Street Journal